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http://hdl.handle.net/10773/5066
Título: | Acetylcholine release and choline uptake by cuttlefish (Sepia officinalis) optic lobe synaptosomes |
Autor: | Nunes, M. Alexandra Santos, Sofia Cordeiro, J. Miguel Neves, Paulo Silva, Virgilia S. Sykes, Antonio Morgado, Fernando Dunant, Yves Goncalves, Paula P. |
Palavras-chave: | ACh Acetylcholine Ch Choline CNS Central nervous system HC-3 Hemicholinium-3 |
Data: | Fev-2008 |
Editora: | Marine Biological Laboratory |
Resumo: | Acetylcholine (ACh), which is synthesized from choline (Ch), is believed to hold a central place in signaling mechanisms within the central nervous system (CNS) of cuttlefish (Sepia officinalis) and other coleoid cephalopods. Although the main elements required for cholinergic function have been identified in cephalopods, the transmembrane translocation events promoting the release of ACh and the uptake of Ch remain largely unsolved. The ACh release and Ch uptake were quantitatively studied through the use of in vitro chemiluminescence and isotopic methods on a subcellular fraction enriched in synaptic nerve endings (synaptosomes) isolated from cuttlefish optic lobe. The ACh release evoked by K+ depolarization was found to be very high (0.04 pmol ACh.s-(1).mg(-1) protein). In response to stimulation by veratridine, a secretagogue (a substance that induces secretion) that targets voltage-gated Na+ channels, the release rate and the total amount of ACh released were significantly lower, by 10-fold, than the response induced by KCl. The high-affinity uptake of choline was also very high (31 pmol Ch.min(-1).mg(-1) protein). The observed ACh release and Ch uptake patterns are in good agreement with published data on preparations characterized by high levels of ACh metabolism, adding further evidence that ACh acts as a neurotransmitter in cuttlefish optic lobe. |
Peer review: | yes |
URI: | http://hdl.handle.net/10773/5066 |
ISSN: | 0006-3185 |
Versão do Editor: | http://www.biolbull.org/content/214/1/1.long |
Aparece nas coleções: | CESAM - Artigos DBio - Artigos |
Ficheiros deste registo:
Ficheiro | Descrição | Tamanho | Formato | |
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Biol Bull 214 (2008) 1.pdf | 157.4 kB | Adobe PDF | Ver/Abrir |
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